Sink



FIG. 1 is a perspective view of a sink showing my new design;

FIG. 2 is a front perspective view of thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side and left side elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a sink, as shown and described. 